With 2.6.34.1 (and also 2.6.33.6) I'm getting the following error
arch/x86/kernel/vmlinux.lds:642: undefined symbol `PMD_SHIFT' referenced in expression
It was previously an issue in 2.6.13.
Configured for AMD32, .config is available at http://wylie.me.uk/tmp/config-2.6.34.1-pax